124 lines
4.6 KiB
C
124 lines
4.6 KiB
C
/* parser and formatter for ASN.1 DER encoding.
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* The parser can read BER encoding, too. */
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#include <stddef.h>
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enum asn1_tagclass {
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UNIVERSAL=(0<<6),
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APPLICATION=(1<<6),
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PRIVATE=(2<<6),
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CONTEXT_SPECIFIC=(3<<6)
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};
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enum asn1_tagtype {
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PRIMITIVE=(0<<5),
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CONSTRUCTED=(1<<5)
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};
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enum asn1_tag {
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BOOLEAN=1,
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INTEGER=2,
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OCTET_STRING=4,
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ENUMERATED=10,
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SEQUENCE_OF=16,
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SET_OF=17,
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};
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/* write int in least amount of bytes, return number of bytes */
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/* as used in ASN.1 tag */
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size_t fmt_asn1tag(char* dest,enum asn1_tagclass tc,enum asn1_tagtype tt,
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unsigned long tag);
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/* write int in least amount of bytes, return number of bytes */
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/* as used in ASN.1 length */
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size_t fmt_asn1length(char* dest,size_t l);
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/* write int in least amount of bytes, return number of bytes */
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/* as used in ASN.1 INTEGER. This only does the payload, not the tag
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* and length headers! */
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size_t fmt_asn1intpayload(char* dest,unsigned long val);
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/* write int in least amount of bytes, return number of bytes */
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/* as used in ASN.1 INTEGER. This only does the payload, not the tag
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* and length headers! */
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size_t fmt_asn1sintpayload(char* dest,signed long val);
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/* write int in least amount of bytes, return number of bytes */
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/* as used in ASN.1 INTEGER or ENUMERATED. */
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size_t fmt_asn1int(char* dest,enum asn1_tagclass tc,enum asn1_tagtype tt,
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enum asn1_tag tag,unsigned long val);
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/* write int in least amount of bytes, return number of bytes */
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/* as used in ASN.1 INTEGER or ENUMERATED. */
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size_t fmt_asn1sint(char* dest,enum asn1_tagclass tc,enum asn1_tagtype tt,
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enum asn1_tag tag,signed long val);
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/* write any data type that does not require transformation in the least
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* amount of bytes, return number of bytes */
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/* as used in ASN.1 OCTET STRING, SEQUENCE etc. */
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/* does not wrote the payload itself, just the header! First construct
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* the sequence/octet string so you know the length, then use
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* fmt_asn1transparent to write the header before it */
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size_t fmt_asn1transparent(char* dest,enum asn1_tagclass tc,
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enum asn1_tagtype tt,enum asn1_tag tag,size_t len);
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/* write string in least amount of bytes, return number of bytes */
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/* as used in ASN.1 OCTET STRING. */
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size_t fmt_asn1string(char* dest,enum asn1_tagclass tc,enum asn1_tagtype tt,
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enum asn1_tag tag,const char* c,size_t l);
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/* write ASN.1 OCTET STRING */
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#define fmt_asn1OCTETSTRING(dest,c,l) fmt_asn1string(dest,UNIVERSAL,PRIMITIVE,OCTET_STRING,c,l)
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/* write ASN.1 INTEGER */
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#define fmt_asn1INTEGER(dest,l) fmt_asn1int(dest,UNIVERSAL,PRIMITIVE,INTEGER,l)
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/* write ASN.1 BOOLEAN */
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#define fmt_asn1BOOLEAN(dest,l) fmt_asn1int(dest,UNIVERSAL,PRIMITIVE,BOOLEAN,l)
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/* write ASN.1 ENUMERATED */
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#define fmt_asn1ENUMERATED(dest,l) fmt_asn1int(dest,UNIVERSAL,PRIMITIVE,ENUMERATED,l)
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/* write ASN.1 SEQUENCE */
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#define fmt_asn1SEQUENCE(dest,l) fmt_asn1transparent(dest,UNIVERSAL,CONSTRUCTED,SEQUENCE_OF,l)
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/* write ASN.1 SET */
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#define fmt_asn1SET(dest,l) fmt_asn1transparent(dest,UNIVERSAL,CONSTRUCTED,SET_OF,l)
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/* conventions for the parser routines:
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* src points to the first byte to parse
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* max points to the first byte behind the buffer
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* the return value is the number of bytes parsed or 0 for parse error */
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/* parse ASN.1 tag into a tag class, tag type and tag number */
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size_t scan_asn1tag(const char* src,const char* max,
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enum asn1_tagclass* tc,enum asn1_tagtype* tt, unsigned long* tag);
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/* parse ASN.1 length */
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size_t scan_asn1length(const char* src,const char* max,size_t* length);
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/* parse ASN.1 integer with tag and length */
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size_t scan_asn1int(const char* src,const char* max,
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enum asn1_tagclass* tc,enum asn1_tagtype* tt, unsigned long* tag,
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long* val);
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/* parse raw integer (payload after tag and length); internal helper */
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size_t scan_asn1rawint(const char* src,const char* max,size_t len,long* val);
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/* parse string with tag and length.
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* Points s to the first byte in the string, and writes the length of
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* the string to l. */
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size_t scan_asn1string(const char* src,const char* max,
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enum asn1_tagclass* tc,enum asn1_tagtype* tt,unsigned long* tag,
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const char** s,size_t* l);
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/* the following expect a specific universal type and return a parse
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* error if the tag does not match that type */
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size_t scan_asn1BOOLEAN(const char* src,const char* max,unsigned long* l);
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size_t scan_asn1INTEGER(const char* src,const char* max,signed long* l);
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size_t scan_asn1ENUMERATED(const char* src,const char* max,unsigned long* l);
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size_t scan_asn1STRING(const char* src,const char* max,const char** s,size_t* l);
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size_t scan_asn1SEQUENCE(const char* src,const char* max,size_t* len);
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size_t scan_asn1SET(const char* src,const char* max,size_t* len);
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